What is the reason why planes are often late?

1. There was a mechanical failure in flight.

2. The weather is bad.

Weather reason:

1. Bad weather conditions at the departure airport caused the delay.

2. The bad weather conditions at the airport did not meet the landing conditions, resulting in delays.

3. The weather conditions over the flight route are not good, which does not meet the flight safety conditions, resulting in delays.

The reason for being in the air:

1. Because the flight of aircraft strictly follows the flight trajectory, all aircraft must fly on a specific flight trajectory. In order to prevent traffic jams or even rear-end collisions between aircraft and other aircraft in the same channel during flight. Airlines will delay the take-off time of aircraft or reduce the flight speed of aircraft in the air on the grounds of flow control.

2. During the flight, due to various reasons, the flight speed can not reach the established speed, which leads to the delay of the aircraft.